Team Fortress 2

Description:
Team Fortress 2 is listed here for an ugly part of its sound design that can be immersion breaking. While viewing the video above, you might notice that you have heard some of the sound before Team Fortress 2 in some other games by Valve, which are the Half-Life games. Those who played through Half-Life (2) before they ever touched Team Fortress 2 may associate the sounds grabbed from that game with the world of Half-Life.
The use of Half-Life sounds in Team Fortress games started with the original Team Fortress, which was a Half-Life mod and used most of it’s resources, including sounds. Team Fortress 2 however was developed as a completely different game, with a bigger budget and a visual style of its own. The sound could and should have evolved with it.
Valve also used sounds from Half-Life in its Portal games. This however is a different case, since the Portal and Half-Life games are actually set in the same universe, while Team Fortress 2 is not. Therefor hearing sounds from this other universe, can remind the player to the fact that the two games and universes were created by the same developer in the same game engine, pulling the player back to reality at the cost of immersion.